An antenna device that transmits and receives radio waves used for a radio broadcast, a GPS, an ETC, or the like is attached to a vehicle such as a car. In Japanese Patent No. 3859630, an antenna device which includes a flexible pad attached to a base on which an antenna and a circuit board are placed, and a cover which covers the circuit board, and the like, and which is attached to an outer plate of the vehicle is described. Since an edge of the cover and the pad in the antenna device are appressed to each other, it is possible to enhance a waterproof property of an internal space of the cover.